This invention relates to biologically active pyrazolidinones. More particularly, this invention is directed to methods for using certain substituted pyrazolidinones which bind to receptors for cholecystokinin (CCK), e.g., those of the brain and pancreas, and to receptors for gastrin, e.g., those of the stomach. The compounds are CCK and gastrin antagonists which are useful in the treatment and prevention of CCK and gastrin-related disorders of the gastrointestinal, central nervous and appetite regulatory systems of warm-blooded vertebrates, especially humans. Examples of such disorders which may be treated using the compounds of this invention include psychosis, anxiety disorders, benzodiazepine cessation and withdrawal, nicotine cessation and withdrawal, smoking cessation, neuroleptic related extrapyramidal motor syndromes, gastrointestinal neoplasms, irritable bowel syndrome and other gastrointestinal motility disorders.